This invention relates to a fluid switch and, more particularly, to a fluid switching element wherein inlet and outlet ports are selectively interconnected in response to external control.
Fluid switches long have been used to control the flow of fluid from a particular source to a destination. Thus, depending upon a particular function which is controlled and a performance which is to be executed, fluid flow can be selectively interrupted to achieve the controlled performance. Accordingly, fluid switches are analogous to electrical switches and, recently, have been used in fluid control systems to minimize power losses and construction costs which previously have been dependent upon the necessity of converting fluid parameters into electrical parameters in order to control the system.
With the advent of fluidic logic systems, it has become desirable to provide various fluidic devices which are analogous to corresponding electrical logic devices. For example, fluidic logic gates, latching elements and other switching elements can be directly disposed in a fluid system to accurately control the operation of that system without necessitating electrical control thereover. Since many fluidic control systems operate with relatively low pressure levels, it has become desirable to provide low-cost fluid switching elements which can operate with such low pressures.
Heretofore, it has been thought that optiminum utilization of a fluid switching element required minimum leakage, and this condition could be attained only by providing positive sealing elements. Thus, in prior fluid switching elements wherein a valve has been used to selectively establish a fluid flow path, such valve was furnished with various sealing elements, such as O-rings, sealing gaskets, sealing gels, and the like. Unfortunately, the use of such positive sealing elements necessitates a relatively high force to be exerted upon the valve to attain a switching condition. The relatively high minimum actuating force which is required to operate such valves has, in turn, required the fluid operating system to be furnished with correspondingly high mechanical forces, and thus is subjected to high energy considerations.
There has been a long-felt need to minimize the energy requirements in a fluid operating system. Accordingly, the various fluid switching elements which can be used with such a fluid operating system should, advantageously, operate with relatively low pressures and, more importantly, should be actuated in response to very low actuating forces. Unfortunately, the requirement of positive sealing elements in such fluid switches has not permitted the desirably low actuating forces to be effective.